AB1045 IS IT POSSIBLE TO DETECT CHRONIC LESIONS ON MRI IN PATIENTS WITH NON-RADIOGRAPHIC AXIAL SPONDYLOARTHRITIS?
Authors: S. Dimitrov, S. Hristova, R. Moraliyska, S. Bogdanova-Petrova, T. Shivacheva, T. Georgiev
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> The absence of categorical radiographic evidence of structural changes in the sacroiliac joints serves to distinguish AS from nr-axSpA. Both groups of patients are characterized by active inflammatory changes, established by magnetic resonance tomography (MRI) of the sacroiliac joints, which, with the progression of the disease, are structurally progressive. <h3>Objectives</h3> To determine whether it is possible to detect erosions, subchondral osteosclerosis and bone marrow metaplasia on a magnetic resonance imaging of the sacroiliac joints in patients with non-radiographic axial spondyloarthritis and symptom duration less than 3 years. <h3>Methods</h3> A cross-sectional survey was conducted with rheumatologists and their consulting patients in Bulgaria from February 2012 through April 2019. Patients who had a rheumatologist confirmed diagnosis of nr-axSpA were eligible to participate. All patients met ASAS criteria for IBP with duration from 3 months to 2 years. All patients had no changes reported after the conventional X-ray of the sacroiliac joints and a performed subsequent MRI. Sacroiliac joint inflammation was assessed using the Canadian Spondyloarthritis Research Consortium (SPARCC). The SPARCC scores of sacroiliac joint inflammation and sacroiliac joint structural damage (SSSD) (erosions, bony brain metaplasia and subchondral osteosclerosis) were evaluated by both - a radiologist and rheumatologist. <h3>Results</h3> A total of 98 patients with non-radiographic were included in this analysis. A higher proportion of patients were male patients (51% vs 37%). The mean age was 33.8±7.71 with mean symptoms duration 0.76±0.26 years. MRI showed bone marrow edema (BME) in all 98 patients and at least 1 structural lesion in 32 patients (92.5%). The most prevalent chronic lesions were erosive changes in 7.14% (n = 7) and narrowed joint space in 7.14% (n = 7). Fat metaplasia was found in 5.10% (n = 5) in the patients with nonradiographic spondyloarthritis. The mean values of SPARCC score in patients with the different arm of nr-ax SpA is 22.42 ± 15.18. The burden of disease activity measured by BASDAI, ASDAS-CRP and VAS as well as ASQoL did not differ in patients with SSSD compared with those with BME only (p&gt;0.05) <h3>Conclusion</h3> Patients with nr-ax SpA are characterized by a short duration of symptoms. Regardless of this recent onset and initially normal X-ray image of the sacroiliac joints, in some patients there are objective data of previous inflammation of the sacroiliac joints that may had not be detected on X-ray. That arise the question of low sensitivity of conventional radiography as well as the presence of risk factors for rapid structural damage and progression in some patients with nr-ax SpA. <h3>References</h3> [1]Baraliakos X, Hermann K, Landewe R, et al. Assessment of acute spinal inflammation in patients with ankylosing spondylitis by magnetic resonance imaging: a comparison between contrast enhanced T1 and short tau inversion recovery (STIR) sequences. Ann Rheum Dis 2005; 64: 1141. [2]Du MS, Xiong XQ, Liu H, Qin X, Hu XF, Chen W. The evaluation of bone marrow edema in sacroiliac joint in patients with ankylosing spondylitis using magnetic resonance imaging Dixon sequence. BMC Musculoskelet Disord. 2021 Nov 1;22(1):919. [3]Carita Tsoi, James Francis Griffith, Ryan Ka Lok Lee, Priscilla Ching Han Wong, Lai Shan Tam, Quant Imaging Med Surg. 2019 Feb; 9(2): 318–335. [4]Braun J, Sieper J, Bollow M. Imaging of Sacroiliitis. Clin Rheumatol, 2000; 19, 51–57. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.